A prior-art fire training system is known from EP 0 535 279 B1, in which fuel jets are generated by distributor tubes with holes in a dispersing medium such as water or pebbles to improve the flammability of the liquid fuel introduced into the unit according to U.S. Pat. No. 4,861,270. An essential drawback of this prior-art unit arises from the effort needed to install the distributor tubes in the dispersing medium as well as from the limited possibilities of specifically changing the flame aspects generated by the distributor tubes installed in the medium.